Heat exchanger and nozzle of heat exchanger

ABSTRACT

In one embodiment, a heat exchanger is provided with an inside shell, an outside shell, a cooling portion, and an inlet nozzle. The inside shell has an inside space for flowing a fluid, and an opening portion for outflowing the fluid from the inside space. The outside shell covers the inside shell to form a first passage between them to flow the fluid outflowing from the opening portion. The cooling portion is disposed within the inside shell to cool the fluid within the inside space. The inlet nozzle has an inner pipe, an outer pipe, and an outlet pipe. The inner pipe flows the fluid into the inside space through the outside shell. The outer pipe covers the inner pipe to form a second passage between them and has its one end connected to the outside shell to communicate the second passage with the first passage, and its other end connected to the inner pipe on the outside of the outside shell to seal the second passage to flow the fluid partly from the first passage to the second passage. The outlet pipe is connected to the outer pipe to inflow the fluid from the second passage.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2010-141734, filed on Jun. 22, 2010; the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a heat exchanger and a nozzle of the heat exchanger

BACKGROUND

There is proposed a nozzle structure for a heat exchanger or the like that a thermal sleeve, which is formed of a cylindrical body having a diameter smaller than that of the nozzle and has its one end attached to the inner peripheral wall on the upstream side of the nozzle, is disposed within the nozzle which is provided to introduce a high-temperature fluid into the main body of the heat exchanger or the like.

But, when the above nozzle structure is used for the heat exchanger in which a heating steam temperature becomes high, thermal stress and creep in the nozzle where the high-temperature steam enters cannot be eased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing a cross section of the structure of the heat exchanger according to one embodiment.

FIG. 2 is a view showing a main portion cross section of FIG. 1.

FIG. 3 is a view showing a main portion cross section of the heat exchanger according to a second embodiment.

FIG. 4 is a view showing a cross section taken along A-A of FIG. 3.

FIG. 5 is a view showing a main portion cross section of the heat exchanger according to a third embodiment.

FIG. 6 is a view showing a main portion cross section of the heat exchanger according to a fourth embodiment.

DETAILED DESCRIPTION

In one embodiment, a heat exchanger is provided with an inside shell, an outside shell, a cooling portion, and an inlet nozzle. The inside shell has an inside space for flowing a fluid, and an opening portion for outflowing the fluid from the inside space. The outside shell covers the inside shell to form a first passage between them to flow the fluid outflowing from the opening portion. The cooling portion is disposed within the inside shell to cool the fluid within the inside space. The inlet nozzle has an inner pipe, an outer pipe, and an outlet pipe. The inner pipe flows the fluid into the inside space through the outside shell. The outer pipe covers the inner pipe to form a second passage between them and has its one end connected to the outside shell to communicate the second passage with the first passage, and its other end connected to the inner pipe on the outside of the outside shell to seal the second passage to flow the fluid partly from the first passage to the second passage. The outlet pipe is connected to the outer pipe to inflow the fluid from the second passage.

In one embodiment, a nozzle of a heat exchanger has an inner pipe, an outer pipe, and an outlet pipe. The inner pipe flows a fluid from outside into an inside space of the heat exchanger. The outer pipe covers the inner pipe to form a passage between them, and has its one end connected to the heat exchanger to communicate the passage with the inside space and its other end connected to the inner pipe on the outside of the heat exchanger to seal the passage to flow the fluid partly from the inside space to the passage. The outlet pipe is connected to the outer pipe to inflow the fluid from the passage.

First Embodiment

Embodiments are described below with reference to the drawings. FIG. 1 is a sectional view showing a cross section of the structure of a heat exchanger 10 according to a first embodiment. FIG. 2 is a view showing a main portion cross section of FIG. 1.

As shown in FIG. 1, the heat exchanger 10 is provided with an outside shell 11 which is formed into a hollow cylindrical shape in which a fluid S such as steam is flown, and an inside shell 12 which is formed into a hollow cylindrical shape and disposed within the outside shell 11. One end of the inside shell 12 is supported by and fixed to a disk-shape tube plate 25 which is disposed at one longitudinal end of the outside shell 11 (right end side of the outside shell 11 in the drawing). An outlet nozzle 18 which allows the fluid S to flow outside is connected to the other longitudinal end of the outside shell 11 (left end side of the outside shell 11 in the drawing).

An opening portion 12 a where the fluid S outflows from the inside shell 12 is disposed on the circumferential surface and on the right end side (tube plate 25 side) of the inside shell 12. Plural heat transfer pipes (hereinafter called as “heat transfer pipe group”) 13 are provided within the inside shell 12. The heat transfer pipe group 13 is pierced through and supported by the tube plate 25. Low-temperature water L flowing from, for example, an unshown water supplier to a boiler is supplied to the heat transfer pipe group 13 to cool down the fluid S within the inside shell 12.

The low-temperature water L flows into a water inlet port 14 and out from a water outlet port 15. A dividing plate 16 divides the water inlet port 14 and the water outlet port 15.

The outside shell 11 covers the inside shell 12 to form a first passage 17, where the fluid S inflowing through the opening portion 12 a flows, between the outside shell 11 and the inside shell 12. The fluid S from the opening portion 12 a, which is formed on the right side of the outside shell 11, flows through the first passage 17 in the left direction in the drawing and outflows from the outlet nozzle 18 which is connected to the left end side of the outside shell 11.

As shown in FIG. 2, an inlet nozzle 19 where a high-temperature fluid (steam) coming from the steam turbine enters is fitted to the circumferential surface and on the left end side of the outside shell 11. The inlet nozzle 19 is comprised of an inner pipe 20, an outer pipe 21 and an outlet pipe 22.

One end of the inner pipe 20 is pierced through the outside shell 11 and attached from the outside to the circumferential surface on the left end side of the inside shell 12, and the fluid S flows from the inner pipe 20 into the inside shell 12. The fluid S from the inner pipe 20 flows within the inside shell 12 in the right direction in the drawing and flows from the opening portion 12 a to the first passage 17.

The outer pipe 21 has an inner diameter larger than the outer diameter of the inner pipe 20 and covers the inner pipe 20 to form a second passage 23 between the outer pipe 21 and the inner pipe 20. One end of the outer pipe 21 is connected to the outside shell 11 to communicate the second passage 23 with the first passage 17. The other end of the outer pipe 21 is connected to the inner pipe 20 on the outside of the outside shell 11 to seal one end of the second passage 23. Thus, the outer pipe 21 forms the second passage 23 between the outer pipe 21 and the inner pipe 20 to inflow partly the fluid S from the first passage 17.

One end of the outlet pipe 22 is connected to the outer pipe 21, and the other end is connected to the outlet nozzle 18. Therefore, the fluid S can be partly outflown from the outer pipe 21 to the outlet nozzle 18 through the outlet pipe 22. The outlet pipe 22 has a bypass function to outflow the fluid S partly from the outer pipe 21 to the outlet nozzle 18.

The fluid S of a high temperature is flown from the inner pipe 20 of the inlet nozzle 19 into the left end of the inside shell 12, moved to the right direction within the inside shell 12 in the drawing, and cooled by the low-temperature water L which flows to make a circuit within the heat transfer pipe group 13. The cooled fluid S outflows from the opening portion 12 a of the inside shell 12 to the first passage 17.

The opening portion 12 a is provided at the right end of the inside shell 12, and the inlet nozzle 19 is provided at the left end of the inside shell 12 away from the opening portion 12 a. As a result, the distance that the fluid S flows in the inside space of the inside shell 12 becomes long, and the fluid S can be cooled efficiently by the heat transfer pipe group 13 as the cooling portion.

The fluid S in the first passage 17 flows along the inner circumferential surface of the outside shell 11 and the outer circumferential surface of the inside shell 12 in the left direction in the drawing and can cool down the outside shell 11 and the inside shell 12. The fluid S in the first passage 17 is flown out of the heat exchanger 10 through the outlet nozzle 18 at the left end of the outside shell 11.

The fluid S from the first passage 17 is partly divided to flow into the second passage 23 of the inlet nozzle 19. The fluid S in the second passage 23 flows upward along the outer circumferential surface of the inner pipe 20 and the inner circumferential surface of the outer pipe 21 in the drawing to cool down the inner pipe 20 and the outer pipe 21. The fluid S in the second passage 23 outflows into the outlet pipe 22. The fluid S in the outlet pipe 22 flows in the left direction in the drawing, joins at the outlet nozzle 18 with the fluid S coming from the first passage 17 and flows out of the heat exchanger 10.

Thus, the heat exchanger of this embodiment is formed with the first passage 17, where the cooled fluid flows, between the outside shell 11 and the inside shell 12 of the double structure and provided with the inlet nozzle 19 which forms the second passage 23 in which the cooled fluid inflows partly. Therefore, the outside shell 11, the inside shell 12 and the inlet nozzle 19 where the high-temperature fluid flows can be cooled down. As a result, the reduction of thermal stress and creep in the heat exchanger and the nozzle 19 can be improved, and the heat exchanger with high reliability can be provided.

In this embodiment, the heat exchanger for cooling the gas such as steam was described, but it is not limited to the above use but can also be applied to a heat exchanger for cooling a liquid such as oil, for example.

Second Embodiment

FIG. 3 is a view showing a main portion cross section of the heat exchanger according to a second embodiment. FIG. 4 is a view showing a cross section taken along A-A of FIG. 3. As shown in FIG. 3 and FIG. 4, the heat exchanger 10 of this embodiment is provided with plural support portions 30 for supporting the inside shell 12 by the inner circumferential surface of the outside shell 11.

The inside shell 12 has an end face 12 b, which is opposed to and away from the tube plate 25, at one longitudinal end of the inside shell 12 (right end of the inside shell 12 in the drawing) to form a space between the tube plate 25 and the end face 12 b. This space functions as a part of the first passage. The end face 12 b serves together with the tube plate 25 to support the pierced heat transfer pipe group 13. The opening portion 12 a through which the fluid S outflows from the inside is disposed on the circumferential surface at the right end of the inside shell 12 and at the end face 12 b.

The fluid S in the first passage 17 flows in the left direction in the drawing along the inner circumferential surface of the outside shell 11 and the outer circumferential surface of the inside shell 12 to cool down the outside shell 11 and the inside shell 12. In addition, the fluid S in the first passage 17 flows downward in the drawing along the end face 12 b and the tube plate 25 to cool down the tube plate 25.

Thus, the heat exchanger of this embodiment provides the same effects as in the first embodiment. And, the inside shell 12 is supported independent of and within the outside shell 11, so that a first route where the cooled fluid flows can also be formed in the space between the end face 12 b and the tube plate 25. As a result, the reduction of thermal stress and creep in the tube plate 25 can also be improved, so that a heat exchanger with higher reliability can be provided.

Third Embodiment

FIG. 5 is a view showing a main portion cross section of the heat exchanger according to a third embodiment. As shown in FIG. 5, the heat exchanger 10 of this embodiment has substantially the same structure as that of the heat exchanger of FIG. 4. But it has the following differences. That is, the tube plate 25 shields one longitudinal end within the outside shell 11 and is disposed below the inside shell 12. As a result, the longitudinal directions of the outside shell 11 and the inside shell 12 become vertical directions in the drawing, and the heat exchanger 10 is vertically disposed.

The inlet nozzle 19 is disposed on the circumferential surface at an upper end side of the outside shell 11. The inner pipe 20 is mounted on the circumferential surface at an upper end side of the inside shell 12 through the outside shell 11 from the outside to flow the fluid S into the inside shell 12.

In the heat exchanger 10, a condensed drain (liquid resulting from condensation of steam) W generated while operating can be held on the side of the tube plate 25, so that a recovery nozzle 31 for outflowing the condensed drain W is mounted on the circumferential surface of the tube plate 25.

The high-temperature fluid S inflows from the inner pipe 20 of the inlet nozzle 19 into an upper end of the inside shell 12 and moves downward in the inside shell 12 in the drawing and is cooled by the low-temperature water L which flows to make a circuit within the heat transfer pipe group 13. The cooled fluid S outflows from the opening portion 12 a of the inside shell 12 to the first passage 17.

The fluid S in the first passage 17 flows along the inner circumferential surface of the outside shell 11 and the outer circumferential surface of the inside shell 12 upward in the drawing and can cool down the outside shell 11 and the inside shell 12. The fluid S in the first passage 17 flows out of the heat exchanger 10 through the outlet nozzle 18 at the upper end of the outside shell 11.

The fluid S in the first passage 17 is divided partly to flow into the second passage 23 of the inlet nozzle 19. The fluid S in the second passage 23 flows in the right direction in the drawing along the outer circumferential surface of the inner pipe 20 and the inner circumferential surface of the outer pipe 21 to cool down the inner pipe 20 and the outer pipe 21. The fluid S in the second passage 23 outflows to the outlet pipe 22. The fluid S in the outlet pipe 22 flows upward in the drawing, joins in the outlet nozzle 18 with the fluid S coming from the first passage 17, and flows out of the heat exchanger 10.

When the heat exchanger 10 is operating, the fluid S condenses in the heat exchanger 10 to generate the condensed drain W. The condensed drain W flows onto the tube plate 25, flows out of the heat exchanger 10 through the recovery nozzle 31, and can be recovered.

Thus, the same effects as in the second embodiment can be obtained by the heat exchanger of this embodiment. In addition, the recovery nozzle 31 can be connected to the tube plate 25. As a result, recovery of the condensed drain W is also facilitated, and a heat exchanger with higher reliability can be provided.

Fourth Embodiment

FIG. 6 is a view showing a main portion cross section of the heat exchanger according to a fourth embodiment. As shown in FIG. 6, this embodiment is an example that the inlet nozzle 19 is mounted on the heat exchanger 10 having a structure with the outside shell 11 only.

This inlet nozzle 19 is mounted on the circumferential surface at the right end side of the outside shell 11. The inlet nozzle 19 is comprised of the inner pipe 20, the outer pipe 21 and the outlet pipe 22 in the same manner as in the first embodiment.

One end of the inner pipe 20 is pierced through the outside shell 11 to contact the right end side of the outside shell 11 from outside, namely to the heat transfer pipe group 13 on a base end side, to flow the fluid S into the outside shell 11. The low-temperature water L flows into and out of the heat transfer pipe group 13.

The outer pipe 21 covers the inner pipe 20 to form the second passage 23 between them. One end of the outer pipe 21 is connected to the outside shell 11 to communicate the second passage 23 with the inside space of the outside shell 11. The other end of the outer pipe 21 is connected to the inner pipe 20 outside the outside shell 11 to seal one end of the second passage 23. Thus, the outer pipe 21 forms the second passage 23, which is joinable to the inside space of the outside shell 11, between the outer pipe 21 and the inner pipe 20, and the fluid S inflows partly from the inside space of the outside shell 11.

The outlet pipe 22 has its one end connected to the outer pipe 21 and the other end connected to the outlet nozzle 18 in the same manner as in the first embodiment, and the fluid S flowing from the outside shell 11 into the second passage 23 is partly bypassed to the outlet nozzle 18.

The high-temperature fluid S flows from the inner pipe 20 of the inlet nozzle 19 into the right end of the outside shell 11, moves in the left direction within the outside shell 11 in the drawing, and is cooled by the low-temperature water L which flows to make a circuit within the heat transfer pipe group 13. The cooled fluid S can cool down the outside shell 11 by flowing in the left direction within the outside shell 11 in the drawing. The fluid S outflows from the outlet nozzle 18 mounted at the left end of the outside shell 11.

The cooled fluid S is divided to flow partly into the second passage 23 of the inlet nozzle 19. The fluid S in the second passage 23 flows upward in the drawing along the outer circumferential surface of the inner pipe 20 and the inner circumferential surface of the outer pipe 21 to cool down the inner pipe 20 and the outer pipe 21. The fluid S in the second passage 23 outflows to the outlet pipe 22. The fluid S in the outlet pipe 22 flows in the left direction in the drawing, joins at the outlet nozzle 18 with the fluid S coming from the outside shell 11 and flows out of the heat exchanger 10.

Thus, according to the heat exchanger of this embodiment, the cooled fluid flows inside the outside shell 11, and the inlet nozzle 19 which forms the passage in which the cooled fluid flows is provided, and the outside shell 11 and the inlet nozzle 19 where the high-temperature fluid flows can be cooled. As a result, reduction of thermal stress and creep in the heat exchanger and the nozzle 19 can be improved, so that the heat exchanger with high reliability can be provided.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions. 

1. A heat exchanger, comprising: an inside shell having an inside space for flowing a fluid, and an opening portion for outflowing the fluid from the inside space; an outside shell covering the inside shell to form a first passage between them to flow the fluid outflowing from the opening portion; a cooling portion disposed within the inside shell to cool the fluid in the inside space; and an inlet nozzle having an inner pipe which flows the fluid into the inside space through the outside shell, an outer pipe which covers the inner pipe to form a second passage between them, has its one end connected to the outside shell to communicate the second passage with the first passage, and its other end connected to the inner pipe on the outside of the outside shell to seal the second passage to flow the fluid partly from the first passage to the second passage, and an outlet pipe which is connected to the outer pipe to inflow the fluid from the second passage.
 2. The heat exchanger according to claim 1, wherein the heat exchanger is further provided with an outlet nozzle which is connected to the outside shell and outflows the fluid inflowing from the first passage; and wherein the outlet pipe outflows the fluid, which has inflown from the second passage, to the outlet nozzle.
 3. The heat exchanger according to claim 1, wherein the inside shell has a cylindrical shape; wherein the heat exchanger is further provided with a support portion for supporting one end of the cylindrical shaped inside shell; and wherein the opening portion is disposed at one end of the inside shell on the side of the support portion.
 4. The heat exchanger according to claim 1, further comprising a support portion for supporting the inside shell within the outside shell, wherein the inside shell also has an end face spaced from the support portion, and the space between the support portion and the end face functions as a part of the first passage.
 5. The heat exchanger according to claim 3, further comprising: an outflowing portion which outflows the fluid accumulated at the support portion by condensation of the steam; and a tube plate which supports the cooling portion, wherein the support portion which shields one longitudinal end within the outside shell and is disposed on the tube plate side away from the inside shell.
 6. A nozzle of a heat exchanger, comprising: an inner pipe which flows a fluid from outside into an inside space of the heat exchanger; an outer pipe which covers the inner pipe to form a passage between them, and has its one end connected to the heat exchanger to communicate the passage with the inside space and its other end connected to the inner pipe on the outside of the heat exchanger to seal the passage to flow the fluid partly from the inside space to the passage; and an outlet pipe which is connected to the outer pipe to inflow the fluid from the passage.
 7. The nozzle according to claim 6, wherein the heat exchanger has an outlet nozzle for outflowing the fluid which has inflown from the inside space, and the outlet pipe outflows the fluid, which has inflown from the inside space, to the outlet nozzle. 